The measurement of magnetic fields has many applications, such as navigation, metal detection in security settings, and oil and mineral prospecting. There is a long-standing need for inexpensive low-power apparatus to detect small changes in magnetic fields over large ranges. Existing apparatus are deficient in one or more of these desirable features.
For example, certain microelectromechanical (MEM) magnetometers only measure changes in magnetic fields over a small range of intensity. Thus, multiple magnetometers, each adjusted to a different range of magnetic field, may be needed to cover a desired range. Also, some magnetometers respond nonlinearly to changes in the magnetic field intensity. Consequently, extensive and complex calibrations are needed to use these magnetometers. In other instances, components of magnetometers can become distorted when moving in response to a change in the magnetic field, thereby altering the physical or electrical response of the magnetometer itself. In still other cases, the fabrication of magnetometers is complex and expensive.
Similarly, other magnetometers like the flux gate magnetometers or the search coils require large size electrical coils to attain high sensitivities. They also require passing large currents through the coils during measurements thereby causing large power consumption.
Other magnetometers like the superconducting quantum interference devices are very sensitive magnetometers, but require cryogenic temperatures to operate.